In response to a demand for miniaturization of a radio frequency circuit, there has been proposed a radio frequency circuit including a plurality of semiconductor chips laminated in three dimensions. For example, a radio frequency circuit is known in which an upper substrate on which a semiconductor chip is mounted is mounted in a recess of a multilayer substrate including a grounded base metal.
Various methods of grounding a circuit and an element formed on a substrate are known. It is known, for example, to insert a projection of a ground metal located on the lower side of a substrate into a through-hole penetrating the substrate, thereby coupling the ground pattern of a circuit formed on the upper surface of the substrate to the ground metal. As another example, it is known to couple a ground terminal of a semiconductor element formed on the upper surface of a substrate to a ground metal formed on the lower surface of the substrate by a solder buried in a through-hole penetrating the substrate.
Related technologies are disclosed in, for example, Japanese Laid-Open Patent Publication No. 2014-183126, Japanese Laid-Open Utility Model Publication No. 63-91173, and Japanese Laid-Open Utility Model Publication No. 05-031251.